Manufacture of soap powders



Patented June 11, 1935 PATENT OFFICE MANUFACTURE or soar rowmins 'Oharles Watson Moore, Warring-ton,

and Horatio Ballantyne, England, assignors to Port Sunlight, England,

Britain Lancaster, Tadworth, Surrey, Lever Brothers Limited, a company of Great No Drawing. Application April 2, 1932, Serial No. 602,870. In Great Britain May 22, 1931 14 Claims.

This invention relates'to the manufacture of soap powders of the kind known as perborate soap powders. V

Such powders contain perborate (usually sodium perborate), soap and sodium silicataand as a rule sodium carbonate, minor proportions of other suitable ingredients being sometimes present. Methods of producing the powders are well known. The characteristic bleaching properties (as distinct from the purely detergent properties) of the powders are dependent upon their content of active or available oxygen. As hitherto manufactured they possess the disadvantage that under certain conditions of storage, particularly when packed in cartons as is usual, they suifer a progressive, more or less gradual, decomposition of the perborate with corresponding loss of active oxygen. Further, it has been found that when they are put into use for washing purposes the bleaching action is frequently affected by the composition of the water employed, being least when the water is very soft and generally, but not always, greatest when the water is moderately hard, hard waters from different sources exhibiting in some cases noteworthy differences in result.

It is the object of the present invention to provide an improved manufacture of the said perborate sodium silicate soap powders, whereby the powders as such will possess greater stability in terms of active oxygen and when used for washing purposes will exhibit greater uniformity of bleaching action whatever the degree of hardness of the water employed. I

The'invention is based on the discovery that .the loss of oxygen from a perborate soap powder containing sodium silicate is greatly decreased by the addition of a small percentage of a suitable salt of magnesium. Thus, it has been found that perborate soap powders containing sodium silicate and magnesium salt losp oxygen far less readily than perborate soap powders containing magnesium salt but no sodium silicate, sodium silicate but no magnesium salt or perborate soap powders alone. In specific tests we have found that if the loss in a given time of oxygen from a perborate soap powder containing sodium silicate and magnesium sulphate be taken as unity the loss of oxygen under s lar conditions from perborate soap powders containing magnesium sulphate but no sodium silicate, sodium silicate but no magnesium sulphate and perborate soap powder alone are as follows:-

Powder coni ..ining magnesium sulphate (1% crystalline magnesium sulphate) but no sodium silicate 4 3 Powder containing sodium silicate but no magnesium sulphate Powder containing neither sodium silicate nor magnesium sulphate 4 3 Suitable salts of magnesium are the sulphate, chloride, and nitrate. Less soluble salts may also be employed, although to less advantage, provided that their fineness of subdivision'and thoroughness of incorporation allow their distribution throughout the product to be sufficiently intimate and uniform.

The percentage of magnesium salt to be employed varies to some extent with the nature and proportions of the other ingredients of the powder, but as a rule a quantity thereof equivalent to from about 0.1 per cent. to about 0.3 per cent. of magnesium oxide (MgO) has been found to be suitable.

The incorporation of the ingredients should be thorough and may be elfected in various ways. In order to minimize any loss of active oxygen during the process, it is best to avoid temperatures exceeding 50 C. when the perborate has been added.

The incorporation of themagnesium compound employed is facilitated by adding it dissolved or suspended in a small quantity of water. It has been found advantageous first to mix the solution or suspension with the soap while the latter is in a pasty or molten condition and thereafter to incorporate the other ingredients, the perborate being preferably added last in order to the risk of loss of active oxygen.

Example To 50 lb. of soap (containing 63% fatty acids] in a pasty or molten condition are added, with thorough mixing, 1 lb. of crystallized magnesium sulphate dissolved in a small quantity of water, 10 lb. of sodium silicate Twad., and 22 lb. of anhydrous sodium carbonate, and to the resulting mixture, when at a temperature not exceeding 50 C., are added 9 /2 lb. of sodium-perborate, the whole being reduced to powder in the known manner.

We claim:

1. A process for the manufacture of a perborate soap powder containing sodium silicate which process comprises incorporating with the other ingredients of the said soap powder a small proportion of a salt of magnesium.

'2. A process for the manufacture of a perborate soap powder containing sodium silicate which process comprises incorporating with the other ingredients of the said soap powder a pro-' portion of magnesium salt substantially equivalent to 0.1 to 0.3 per cent of magnesium oxide (MgOJ 3. A process for the manufacture of a perborate soap powder containing sodium silicate which process comprises incorporating with the other ingredients of said soap powder 0.6 to 1.8 per cent of crystallized magnesium sulphate (MgSOa'lHzO) 4. A process for the manufacture of a perborate soap powder containing sodium silicate which process comprises dissolving a soluble magnesium salt in a small amount of water incorporating this solution with the soap when the latter is in the molten or semi-solid condition and thereafter adding the other constituents.

5. A process for the manufacture of a perborate soap powder containing sodium silicate which process comprises suspending a sparingly soluble salt of magnesium in a small amount of water, incorporating this suspension with the soap when the latter is in the molten or semisolid condition and thereafter adding the other constituents.

6. A process for the manufacture of a perborate soap powder containing sodium silicate which process comprises dissolving in a small amount of water an amount of magnesium salt equivalent to 0.1 to 0.3 per cent of magnesium oxide (MgO) on the weight of the soap powder,

incorporating this solution with the soap when the latter is in the molten .or semi-solid condition and thereafter adding the other constituents.

'7. A process for the manufacture of a perborate soap powder containing sodium silicate which process comprises suspending in a small amount of water an amount of a sparingly soluble magnesium salt equivalent to 0.1 to 0.3 per cent of magnesium oxide (MgO) by weight on the soap powder, incorporating this solution with the soap when the latter is in the molten or semisolid condition and thereafter adding the other constituents.

8. As an article of manufacture a perborate soap powder containing sodium silicate and a stabilizing substance consisting of a small proportion of a salt of magnesium.

9. As an article of manufacture a perborate soap powder containing sodium silicate and a stabilizing substance consisting of a salt of magnesium in amount equivalent to 0.1 per cent to 0.3.per cent of magnesium oxide (MgO) on the weight of the soap powder.

10. As an article of manufacture a perborate soap powder containing sodium silicate and as stabilizing substance a soluble or sparingly soluble magnesium salt in amount equivalent to 0.1 per cent to 0.3 per cent of magnesium oxide (MgO) on the weight of the soap powder intimately incorporated therewith.

11. As an article of manufacture a perborate soap powder containing sodium silicate and as stabilizing substance magnesium sulphate uniformly distributed therein in amount equivalent to 0.1 per cent to 0.3 per cent of magnesium oxide (MgO) on the weight of the soap powder.

12. As an article of manufacture a perborate soap powder containing sodium silicate and magnesium chloride uniformly distributed therein as stabilizing substance in amount equivalent to 0.1 per cent to 0.3 per 'cent of magnesium oxide (MgO) on the weight of the soap powder.

13. As an article of manufacture a perborate soap powder containing sodium silicate and as stabilizing substance magnesium nitrate uniformly distributed therein in amount equivalent to 0.1 per cent to 0.3 per cent of magnesium oxide (MgO) on the weight of the soap powder.

14. As an article of manufacture a perborate soap powder containing sodium silicate and as stabilizing substance crystallized magnesium sulphate uniformly distributed therein in amount equivalent to 0.6 to 1.8 per cent MgSOHHzO on the weight of the soap powder.

CHARLES WATSON MOORE. HORATIO BALLANTYNE.

' CERTIFICATE OF CORRECTION.

Patent No. 2,004,670.

the above numbered patent requiring correction as follows:

strike out the character d with this correction there case in the Patent Office.

ed this 14th day April, A. D. 1936.

column, line 53, ent should be rea the record of the (Seal) Signed and seal June 11, 1935 Page 1, first in that the same may conform Leslie Frazer Acting Commissioner of Patents.

and that the said Letters Pat- CERTIFICATE OF CORRECTION.

Patent No. 2,004,670) June 11, 1935.

CHARLES WATSON MOORE, ET AL.

It is hereby certified that error appears in the printed specification of the above numbered patent requiring correction as follows: Page 1 first column, line 53, strike out the character a"; and that the said Letters Patent should be read with this correction therein that the same may conform to the record of the case in the Patent Office.

Signed and sealed this 14th day April, A. D. 1936.

Leslie Frazer (Seal) Acting Commissioner of Patents. 

